welcome to GoY.

It is safe to put it on the compost heap, but I wouldn't add it direct to plants. Apart from anything else the smell would become unpleasant after a while. Urine's pH can be acidic or alkaline depending on how your kidneys are processing what you have been eating and drinking. This pH fluctuation can be detrimental to plants.

Human urine is very strong. Recommended dilution is one part to 20 of water. So, like Seaburn,i would not really think it would be good for plants at that strength and regularly used.